In the Linux kernel, the following vulnerability has been resolved:
drm/vmwgfx: drop dma_buf reference on foreign-fd prime import
ttm_prime_fd_to_handle() returns -ENOSYS when the imported fd’s
dma_buf->ops do not match the ttm_object_device’s ops, but does so
without releasing the reference acquired by dma_buf_get(). Any
unprivileged renderD client passing a non-vmwgfx prime fd through the
DRM_VMW_GB_SURFACE_REF{,_EXT} path leaks one dma_buf reference per
call and indefinitely pins the foreign exporter’s GEM resources.
Funnel the error path through the existing dma_buf_put() so the
reference is always dropped.
